关键词: 长江流域, 积温, 农业适应性, 时空变化

Abstract: Analysis was done of the data of daily mean temperature of the recent 50 years (1961 – 2010) from the 659 meteorological stations in the Yangtze River Basin using the linear trend estimation method and GIS spatial analysis method for ≥0 ℃ accumulated temperature, duration of the days ≥0 ℃and tempro-sparial distribution of the beginning and ending of the peiord. Results show that in the past 50 years, the annual mean temperature in the basin is rising slowly with a tendency rate reaching to 0.18 ℃·d·(10 a) ^-1 and amplitude of the change is lower than the warming rate of the country during the same period. The annual mean ≥0℃ accumulated temperature was 5496.77 ℃·d with a tendency rate being 69.92 ℃·d·(10 a)^-1 in the Yangtze River Basin, of which the middle reaches were the highest in annual mean ≥0℃ accumulated temperature and the upper reaches were the lowest. The mean duration was 342.25 d with a trend rate being 2.51 d·(10 a)^-1. The middle reaches were also the highest in duration, being 350.55 d and the lower reaches were in the tendency rate, being 3.73 d·(10 a)^-1. The beginning date of the duration was advanced and the ending date postponed. The duration was steadily increasing year by year, which was mainly attributed to the advancement of the beginning date. The decadal variation of accumulated temperature displayed V shaped curve, which began to increase significantly in the 90s, while the number of days between the beginning and ending of the ≥0℃ accumulated temperature period increased steadily with the decases. The increase was more significant in the 1970s - 1990s.Spatial analysis shows that an increasing tendency went gradually from northwest to southeast. However, there were two distinct high value areas, one in the west Sichuan Basin, and the other in the southeast of the river basin, including south Hunan and southeast Jiangxi and one low value area that the Tongtian River Basin. The contours of accumulated temperatures moved westward slowly with decades passing by. Besides moving westward, the contour of 6 000 ℃, has also been moving northward significantly since the 1990s. Compared with the 1960s, accumulated temperature increased in the whole Yangtze River Basin, except for a small region in Sichuan Province in 2000s. In response to the increase in accumulated temperature, it is necessary to take some measures, like use of new crop varieties and crop rotation systems that are more suitable to warm weather, so as to avoid waste of the heat resources and prevent damage of increased heat resourcs to crop growth in the Yangtze River Basin.

Key words: Yangtze River Basin, accumulated temperature, agricultural adaptation, temporal and spatial variation